This is odd, in a way, since it's an established phenomenon that top players tend to set the fashion in openings, not only for other grandmasters, but for chessplayers in general. Nothing else can explain the interest that players who can barely remember the theory beyond move five show in the Najdorf, as if the fact that Kasparov and Fischer played it must perforce mean that it is a deadly weapon in their hands. Well, an atom bomb would be a deadly weapon in my hands but I wouldn't actually like to touch one, and that goes for the Najdorf too.
Anyway, if there are openings which are rather more popular at our level than at the level where the good players are, it must surely mean that the opposite is true. There are surely fewer Petroffs at our level than at the highest, possibly because the club player's repertoire is necessarily limited and you can't afford to spend time on an opening which gives White a draw when they might be forty ECF points worse than you. (Of course, if we stuck to our openings, you might learn a more combative opening very well and then add the Petroff to your repertoire. But we tend rather to change than add.) You also see rather fewer Semi-Slavs from club players than from supergrandmasters: mind you it'd be hard not to, as they're barely playing anything else in Mexico City.
However, there's a couple of opening variations, frequently seen in grandmaster praxis, that I've seldom or never seen, in any club match I've played in or any tournament game I've seen, save for grandmasters on the high boards of a very strong open. Variations which, for one reason or another, are basically absent from the repertoires and the thoughts of club players. One of these is the Marshall Gambit in the Lopez, which is currently considered so sound that it is more often avoided by White than actually played by Black. Indeed, it's got to the point that I rarely recognise a grandmaster Lopez any more, since rather than use the order 7...d6 8.c3 O-O 9.h3 that I play and love, everybody goes 7...O-O then 8.a4 or 8.h3 Bb7 and we get into positions which are not quite the ones I know.
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 Ba4 Nf6 5.O-O Be7 6.Re1 b5 7.Bb3 O-O 8.c3 d5
You do, however, still see a lot of the position above when grandmasters play, one leading swiftly by way of 9.exd5 Nxd5 10.Nxe5 Nxe5 11.Rxe5 to the position below:
and sometimes White wins quickly! In fact it looks like a position offering decent and comprehensible play for a pawn, which indeed it does, very much the sort of thing that attracts club players to, say, the Benko Gambit. But, unlike that less-sound gambit, among club players it is rarely seen. Very rarely indeed. In fact, I'll go so far as to say that in my thirty-year experience I've seen it, to my recollection, precisely once. I remember that, because I was playing it, with the Black pieces. I got beaten convincingly. I didn't play it again, which might normally be considered an extreme reaction, but I think was fairly sound: you have to remember an enormous amount of theory to play it, theory which you will almost never get to play anyway. And if you do, it will be to little purpose because the only people to play down the main lines will be people who know them well themselves.
That's a big difference between club players and grandmasters, as regards the openings. They can and must assume that the opponent knows existing theory. They therefore look for novelties. We, however, seek only to know more than the opponent. Which is pointless, if they'll never let you show it. Or if you'll only get to play the theory when, in fact, you don't know more of it than they do.
Added to that, the fact that the Marshall won't, in many lines, give you more than a draw, and you can see why it's rarely seen (though not, perhaps why quite so rarely). I once saw the estimable Tim Harding recommend it as an ideal choice for the club player, or a phrase similar to that. I thought that was completely wrong. I think it is the opposite.
The neglect of the Marshall, I can understand. But there's another line I can think of which, while being not at all rare in published games, I cannot recall seeing ever except when played by a professional. Unlike the Marshall, it's a line that White chooses, it's not grotesquely complicated and if there's draws to be had, they're probably available to White rather than Black. It's not attached to a rare opening, it being a line of the Queen's Gambit Declined, and there's even been a decent book about it, written a few years ago by Colin Crouch. It goes as follows:
1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Nf3 Be7 5.Bf4
Maybe I've just been looking in the wrong direction, I dunno. But I've not seen it played. Never. Not once. I wonder why not?